This is a note to let you know that I've just added the patch titled powerpc/perf/hv-24x7: add missing RTAS retry status handling to the 5.10-stable tree which can be found at: http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git;a=summary The filename of the patch is: powerpc-perf-hv-24x7-add-missing-rtas-retry-status-h.patch and it can be found in the queue-5.10 subdirectory. If you, or anyone else, feels it should not be added to the stable tree, please let <stable@xxxxxxxxxxxxxxx> know about it. commit a72f9c204014cb6ccab13652be468da836c1b8fe Author: Nathan Lynch <nathanl@xxxxxxxxxxxxx> Date: Fri Feb 10 12:41:50 2023 -0600 powerpc/perf/hv-24x7: add missing RTAS retry status handling [ Upstream commit cc4b26eab1859fa1a70711872caaf6414809973f ] The ibm,get-system-parameter RTAS function may return -2 or 990x, which indicate that the caller should try again. read_24x7_sys_info() ignores this, allowing transient failures in reporting processor module information. Move the RTAS call into a coventional rtas_busy_delay()-based loop, along with the parsing of results on success. Signed-off-by: Nathan Lynch <nathanl@xxxxxxxxxxxxx> Fixes: 8ba214267382 ("powerpc/hv-24x7: Add rtas call in hv-24x7 driver to get processor details") Signed-off-by: Michael Ellerman <mpe@xxxxxxxxxxxxxx> Link: https://lore.kernel.org/r/20230125-b4-powerpc-rtas-queue-v3-2-26929c8cce78@xxxxxxxxxxxxx Signed-off-by: Sasha Levin <sashal@xxxxxxxxxx> diff --git a/arch/powerpc/perf/hv-24x7.c b/arch/powerpc/perf/hv-24x7.c index 6e7e820508df7..1cd2351d241e8 100644 --- a/arch/powerpc/perf/hv-24x7.c +++ b/arch/powerpc/perf/hv-24x7.c @@ -79,9 +79,8 @@ static u32 phys_coresperchip; /* Physical cores per chip */ */ void read_24x7_sys_info(void) { - int call_status, len, ntypes; - - spin_lock(&rtas_data_buf_lock); + const s32 token = rtas_token("ibm,get-system-parameter"); + int call_status; /* * Making system parameter: chips and sockets and cores per chip @@ -91,32 +90,27 @@ void read_24x7_sys_info(void) phys_chipspersocket = 1; phys_coresperchip = 1; - call_status = rtas_call(rtas_token("ibm,get-system-parameter"), 3, 1, - NULL, - PROCESSOR_MODULE_INFO, - __pa(rtas_data_buf), - RTAS_DATA_BUF_SIZE); + do { + spin_lock(&rtas_data_buf_lock); + call_status = rtas_call(token, 3, 1, NULL, PROCESSOR_MODULE_INFO, + __pa(rtas_data_buf), RTAS_DATA_BUF_SIZE); + if (call_status == 0) { + int ntypes = be16_to_cpup((__be16 *)&rtas_data_buf[2]); + int len = be16_to_cpup((__be16 *)&rtas_data_buf[0]); + + if (len >= 8 && ntypes != 0) { + phys_sockets = be16_to_cpup((__be16 *)&rtas_data_buf[4]); + phys_chipspersocket = be16_to_cpup((__be16 *)&rtas_data_buf[6]); + phys_coresperchip = be16_to_cpup((__be16 *)&rtas_data_buf[8]); + } + } + spin_unlock(&rtas_data_buf_lock); + } while (rtas_busy_delay(call_status)); if (call_status != 0) { pr_err("Error calling get-system-parameter %d\n", call_status); - } else { - len = be16_to_cpup((__be16 *)&rtas_data_buf[0]); - if (len < 8) - goto out; - - ntypes = be16_to_cpup((__be16 *)&rtas_data_buf[2]); - - if (!ntypes) - goto out; - - phys_sockets = be16_to_cpup((__be16 *)&rtas_data_buf[4]); - phys_chipspersocket = be16_to_cpup((__be16 *)&rtas_data_buf[6]); - phys_coresperchip = be16_to_cpup((__be16 *)&rtas_data_buf[8]); } - -out: - spin_unlock(&rtas_data_buf_lock); } /* Domains for which more than one result element are returned for each event. */